Cisco Systems Inc. plans to add voice-over-Wi-Fi capabilities to its existing iPhone app by April, part of a continuing effort to expand its unified communications technology into the mobile space.

The current iPhone Cisco Mobile app requires users to have a Cisco Unified Mobility Advantage server installed at a business. The server is usually administered by a company's IT department.

Cisco Mobile already gives iPhone users quick access to many of the standard Cisco IP features, such as visual voicemail and Mobile Connect, software that can route calls from a work number through a company's phone switching network and then out to an iPhone. The iPhone client software is free.

Cisco sees voice over Wi-Fi for the iPhone as a less expensive way to communicate because it would eliminate the need to use cellular voice minutes when placing a call in a Wi-Fi zone, said Laurent Philonenko, general manager of Cisco's unified communications business unit.

The upcoming version, to be called Cisco Mobile Voice, will also be free and is expected to be available by April. Among the new features it will offer is "shake to lock," which allows a user to end a call with a simple shaking gesture of the phone, he said. Another, named "call preservation," allows a phone call to stay connected, even if a user opens a different application in the iPhone.

Philonenko spoke to reporters in Boston and other cities from San Jose, Calif., via videoconference and was joined in Madison, Wisc., by Pat Scheckel, vice president of converged infrastructure solutions for CDW, which resells computers and related gear to businesses.

CDW, which has 3,500 customer deployments of Cisco's mobile and unified communications technology globally, has already worked with one manufacturing company that has implemented voice over Wi-Fi using Nokia smartphones and Cisco 7925 IP phones, Scheckel said. "They had exorbitant cell phone bills and now just use Wi-Fi," he noted.

Philonenko said it is important for Cisco to bring its mobility apps to iPhone, which has gained ground in large businesses in the past two years. Cisco eventually plans to bring all of its mobility applications to Nokia and BlackBerry devices, and, later, Android phones, he said. "Android is not yet a big factor in the enterprise," he said. "And we think Windows Mobile will re-emerge....

"The iPhone came from nowhere and companies like CDW are now deploying them by the thousands," Philonenko said. With smartphone devices proliferating, cell networks seem to have saturated the globe, "but there's still not enough 3G bandwidth for what people want to do." As a result, Wi-Fi is seen as a relief valve, raising the value of voice over Wi-Fi, he added.

Cisco, which offers Webex collaboration software as well, is tracking the growing importance of social networking, Philonenko added. "Everything we do [at Cisco] is going to be mobilized," he said.

Editor's note:This story has been changed since it was originally posted to remove a paragraph regarding an iPhone application for voice-activated dialing. Cisco Systems said the app was unintentionally included as part of Web 2.0 IP Telephony Widget. Cisco said the average consumer cannot download the widget and the information was not part of Cisco's announcement.